MIAMI The problem with the Marlins’ lack of offense starts at the top.

Marlins leadoff hitters ranked last in the National League with six runs scored through Sunday, and their .200 batting average was second-to-last.

After a two-day experiment with Emilio Bonifacio batting leadoff ahead of Jose Reyes, manager Ozzie Guillen flipped them again with Reyes back in the top spot for Monday’s series finale with the Diamondbacks.

Bonifacio, who excelled as a leadoff hitter last year, was 1-for-8 with one walk in those two games. More troubling, he struck out five times to move into the team lead with 22.

That surprised me because Boni’s game should be put the ball in play,” Guillen said. “I expect better contact. Especially from Boni. Boni’s game is speed.”

Bonifacio, in a 6-for-40 (.150) slump, said Sunday that he has not been comfortable at the plate lately.

“I’m swinging at a lot of pitches outside the [zone],” he said. “I’m not giving up. I’ll fix my approach.”

Back in the bigs

Bryan Petersen is used to the yo-yo routine of trying to stick in the major leagues, but it took a moment to calculate how many times he has been called up by the Marlins.

“Fifth? No, sixth,” said Petersen, who was summoned Sunday afternoon from Triple-A New Orleans. He joined the Marlins on Monday along with reliever Dan Jennings, who will be getting his first big-league look.

“It’s like my sixth time. I’m super excited, but a little bit more on the mellow side. You could see how excited [Jennings] was,” said Petersen. “I’m super happy for him. It’s an awesome feeling to come out on this field and be a part of this. It’s cool for him.”

Petersen, an outfielder who batted .264 with two home runs in 74 games with the Marlins last season, was hitting .316 for the Zephyrs. He replaces Chris Coghlan on a team in dire need of an offensive spark.

“I don’t know if that can necessarily be put on one person or not. I hope to bring some form of positive energy to the clubhouse,” said Petersen, who little time to contemplate his role.

“It’s been a crazy past 14 hours,” he said. “I had an hour and a half to get to the airport. … So I’m missing a lot of stuff, but I’ll be all right.”

Jennings, the Marlins’ ninth-round draft pick out of Nebraska in 2008, had a 2.08 ERA with 10 strikeouts in nine appearances over 8 2/3 innings.

In 2010, Jennings received a 50-game suspension for violating minor league baseball’s drug policy. The substance was methylhexanemine, a stimulant, not a steroid. The product recommended to Jennings, which he bought over the counter at a supplement shop, delivered the equivalent jolt of four cups of coffee.

About a week after Major League Baseball announced Jennings’ suspension, five other minor-leaguers tested positive for the same violation.

In a 2011 interview, Jennings told the Sun Sentinel: “It was something you would never think [was banned]. … I bought it, took it for a month, ran out, bought it again, and two months later…that’s what happens. I’m not going to say I was stupid, but I wasn’t smart.”